After two storms left nearly 1 million homes and businesses without power in 2012, Connecticut began testing whether small electric grids can provide power even when the main grid loses it.

On the afternoon of June 29, a severe thunderstorm tore across the Midwest and Mid-Atlantic. By day’s end, the intense storm, called a “derecho,” had left 22 people dead and millions without power (some for as long as a week) in six states and the District of Columbia.

The power outages left customers fuming. But more frustrating was a sense that blackouts were becoming normal. In 2011, more than 3,000 outages in the U.S. affected 41.8 million people, according to the Eaton Corp., which tracks blackouts. That’s up from 2,169 power outages that affected 25 million people in 2008.

Volatile weather is largely to blame for the increase in outages. But the underlying issue is an aging energy grid that, according to a 2005 report by the U.S. Navy’s Inspector General, is “stressed by relentlessly increasing demand, operating at near capacity with decreasing staffs and reliant on electronic components.”

Last year, after two storms left nearly 1 million Connecticut businesses and home-owners without power, Gov. Dannel Malloy had had enough. He formed a panel to look for ways to avoid future outages. The group came back with the usual suggestions, like burying power lines. But their report also included another less familiar idea: microgrids.

A microgrid is essentially a small electric grid with its own generation source, such as fuel cells, wind, solar or other energy sources. It’s usually linked to a main electric grid, but “its distinguishing feature is that it if a utility shuts down, a microgrid can disconnect itself and operate in ‘island mode,’” says Peter Asmus, a microgrid expert and senior research analyst at Boulder, Colo.-based Pike Research. In other words, a microgrid can provide power to college campuses, neighborhoods, industrial facilities and military bases, while retaining the ability to operate independently if the main grid loses power.

In June, the Connecticut General Assembly created a microgrid pilot program, making it the first state to have an explicit policy on microgrids. The Department of Energy and Environmental Protection (DEEP) was given $20 million to test the idea with a handful of municipalities, which will be selected by the end of the year, with several microgrids operating by mid-2013. The idea is not only to strategically place microgrids near critical facilities, such as hospitals, police and fire stations, and water systems, but also near town centers and commercial hubs. That way, if the power goes out, grocery stores, gas stations and pharmacies will remain open too.

Connecticut’s microgrid pilot will be the technology’s first real case study. There are certainly other microgrids operating in the U.S. -- for example, the Santa Rita Jail in Dublin, Calif., runs on one; the University of California at San Diego has a microgrid that operates on a mixture of renewable and traditional energy sources; and the U.S. Department of Energy is currently spending $55 million to support eight microgrid projects. Still, there are no regulations governing the technology, according to Asmus. So it will be up to Connecticut to develop technical, operational and safety standards. The state also must figure out funding. For now, Connecticut’s plan is that the cost will be borne by all ratepayers, including the businesses tied into the system.

There are about 270 microgrids worldwide, according to Pike Research. And because “we have a much higher rate of power outages [than other countries], we are the leading market for microgrids,” says Asmus. (That market will generate more than $3 billion in annual revenue by 2015, say commercial research firms.) But there are green benefits as well: Because they generally rely on cleaner energy sources, microgrids are more environmentally friendly than big power grids. And since they’re located near the point of demand, the electricity doesn’t have to travel as far, so less power is lost in transmission and distribution.

Photo of the Santa Rita Jail’s microgrid, which gets some of its energy from solar panels, by Chris Marnay/Berkeley Lab.